A typical jaw crusher includes a stationary jaw and a moveable jaw spaced to define a crushing chamber in between. Aggregate material is fed into the crushing chamber and is crushed by cooperating corrugations on the face of each of the jaws as the moveable jaw is moved repeatedly toward and away from the stationary jaw.
The jaws experience tremendous forces during operation of the crusher, and it is thus important that the stationary jaw be firmly secured to the crusher frame during operation. For example, due to the angle between the moveable jaw and the stationary jaw, the moveable jaw repeatedly applies a cyclic, upward force against the stationary jaw. Any undesired movement of the stationary jaw leads to excess wear and tear, increased down time, and hence increased operational cost of the crusher. It is thus critical that the stationary jaw be firmly secured against any up and down movement.
The tremendous forces against the jaw faces also causes the jaw faces to wear much faster than the remaining crusher components. Moreover, because of the angle between the stationary jaw and the moveable jaw alluded to above, the bottom portion of the jaw face tends to wear faster than the top portion of the jaw face. Consequently, the face of the stationary jaw is symmetrical, and the stationary jaw is removable, so that jaw can be removed, rotated, and re-installed so that the life of the jaw is effectively doubled. Accordingly, it is important that the jaws be easily attachable and removable from the crusher frame.
The crusher frame typically includes a top cross member and a bottom cross member, while the jaw includes a top lug positioned to overlie the top cross member and bottom lug positioned to underlie the bottom cross member. Traditional practice has been to insert shims between the top lug and the top cross member to draw the jaw upwardly, such that the bottom lug is wedged against the bottom cross member, thus securing the jaw to the frame. The shims were then welded in place.
Unfortunately, the use of shims, which must be sized in discrete sizes, makes it difficult to find the right size shim to exert the desired amount of upward force against the jaw. Moreover, because the shims must be welded in place and then cut away in order to tighten remove, replace, and/or flip the jaw, access must be gained to the middle of the crusher. Gaining such access is often difficult, time consuming, and hence expensive, as other components such as bypass chutes or conveying equipment is often in the way. Moreover, the repeated welding, cutting, and re-welding of the shims often damages the crusher frame.
Accordingly, an improved system for securing the stationary jaw to the jaw crusher frame is desired.